searched twice. u.s. coast guard and the mexican navy are also involved. >>> coming up, what too much social media can do to teenagers and the new advice from doctors. >>> plus, a royal wedding alert. who could try to steal the spotlight from prince william and kate middleton. ,,,,,,,,,,,,,,,,,, doctors are now warning that t >>> so could there be a dark side to using facebook? doctors are now warning that the social media site can have potentially harmful effects on teens' mental health. kit dough has the warning signs and advice for parents. >> reporter: when giovana mendosa started using facebook she noticed something peculiar. everyone's lives are just so happy and perfect. >> nobody really wants to broadcast what is sad or negative in their life. and so it is only going to be the positive that shows up on there. >> reporter: at 22 years old, with 424 friends, she knows better that the image on facebook is not always what it seems. today, the american academy of pediatrics released its updated report called "the impact of social media on children, adolescents and families" and the